A traditional base phone and additional phone are often based on an analog phone deployed at home or in an enterprise, and functions of the traditional base phone and additional phone are supported in a physical parallel connection or wireless manner. Several phones in a set of base phone and additional phone share one operator number resource, and functions such as answering a call by any phone, making a call by any phone, and internal intercom, can be implemented.
An existing base phone and additional phone based on an analog phone generally have two connection modes. One is that all phone sets are connected using a physical line, and the other one is that the base phone is connected to a physical line and added with a wireless communications module in order to implement wireless connection between the base phone and the additional phone.
As mentioned above, the traditional base phone and additional phone are generally based on an analog phone. However, with the development of communications technologies, an analog phone is gradually replaced by an IP terminal, such as an IP telephone. In an evolution process of out with the copper, in with the fiber, that is, “narrowband+copper cable” is replaced with “broadband+optical fiber”, the traditional analog phone and the base phone and additional phone based on an analog phone are facing a situation of being phased out as their disadvantages are becoming more obvious.
Disadvantages of the analog base phone and additional phone lie in that the base phone and additional phone based on an analog phone, in either of the foregoing modes, are connected in a manner of physical parallel connection of copper cables, which lacks security protection and is theft-prone. In addition, when one phone is in a call, a line is occupied, and another phone cannot initiate a new call.